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Shadow detection in very high spatial resolution aerial images: A comparative study / Karine R.M. Adeline in ISPRS Journal of photogrammetry and remote sensing, vol 80 (June 2013)
[article]
Titre : Shadow detection in very high spatial resolution aerial images: A comparative study Type de document : Article/Communication Auteurs : Karine R.M. Adeline, Auteur ; M. Chen, Auteur ; Xavier Briottet , Auteur ; S.K. Pan, Auteur ; Nicolas Paparoditis , Auteur Année de publication : 2013 Article en page(s) : pp 21 - 38 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image optique
[Termes IGN] analyse comparative
[Termes IGN] canyon urbain
[Termes IGN] détection d'ombre
[Termes IGN] image hyperspectrale
[Termes IGN] image multibande
[Termes IGN] rayonnement lumineux
[Termes IGN] rayonnement proche infrarouge
[Termes IGN] seuillage d'image
[Termes IGN] simulation numérique
[Termes IGN] test de performanceRésumé : (Auteur) Automatic shadow detection is a very important pre-processing step for many remote sensing applications, particularly for images acquired with high spatial resolution. In complex urban environments, shadows may occupy a significant portion of the image. Ignoring these regions would lead to errors in various applications, such as atmospheric correction and classification. To better understand the radiative impact of shadows, a physical study was conducted through the simulation of a synthetic urban canyon scene. Its results helped to explain the most common assumptions made on shadows from a physical point of view in the literature. With this understanding, state-of-the-art methods on shadow detection were surveyed and categorized into six classes: histogram thresholding, invariant color models, object segmentation, geometrical methods, physics-based methods, unsupervised and supervised machine learning methods. Among them, some methods were selected and tested on a large dataset of multispectral and hyperspectral airborne images with high spatial resolution. The dataset chosen contains a large variety of typical occidental urban scenes. The results were compared based on accurate reference shadow masks. In these experiments, histogram thresholding on RGB and NIR channels performed the best with an average accuracy of 92.5%, followed by physics-based methods, such as Richter’s method with 90.0%. Finally, this paper analyzes and discusses the limits of these algorithms, concluding with some recommendations for shadow detection. Numéro de notice : A2013-296 Affiliation des auteurs : LASTIG MATIS+Ext (2012-2019) Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.isprsjprs.2013.02.003 Date de publication en ligne : 03/04/2013 En ligne : http://dx.doi.org/10.1016/j.isprsjprs.2013.02.003 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=32434
in ISPRS Journal of photogrammetry and remote sensing > vol 80 (June 2013) . - pp 21 - 38[article]Exemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 081-2013061 RAB Revue Centre de documentation En réserve L003 Disponible Sensitivity of spectral reflectance values to different burn and vegetation ratios: A multi-scale approach applied in a fire affected area / Magdalini Pleniou in ISPRS Journal of photogrammetry and remote sensing, vol 79 (May 2013)
[article]
Titre : Sensitivity of spectral reflectance values to different burn and vegetation ratios: A multi-scale approach applied in a fire affected area Type de document : Article/Communication Auteurs : Magdalini Pleniou, Auteur ; Nikos Koustias, Auteur Année de publication : 2013 Article en page(s) : pp 199 - 210 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection
[Termes IGN] affinage d'image
[Termes IGN] analyse comparative
[Termes IGN] classification par maximum de vraisemblance
[Termes IGN] Grèce
[Termes IGN] image Ikonos
[Termes IGN] image Landsat-SWIR
[Termes IGN] image Terra-ASTER
[Termes IGN] incendie de forêt
[Termes IGN] rayonnement proche infrarouge
[Termes IGN] régression multiple
[Termes IGN] sol nuRésumé : (Auteur) The aim of our study was to explore the spectral properties of fire-scorched (burned) and non fire-scorched (vegetation) areas, as well as areas with different burn/vegetation ratios, using a multisource multiresolution satellite data set. A case study was undertaken following a very destructive wildfire that occurred in Parnitha, Greece, July 2007, for which we acquired satellite images from LANDSAT, ASTER, and IKONOS. Additionally, we created spatially degraded satellite data over a range of coarser resolutions using resampling techniques. The panchromatic (1 m) and multispectral component (4 m) of IKONOS were merged using the Gram-Schmidt spectral sharpening method. This very high-resolution imagery served as the basis to estimate the cover percentage of burned areas, bare land and vegetation at pixel level, by applying the maximum likelihood classification algorithm. Finally, multiple linear regression models were fit to estimate each land-cover fraction as a function of surface reflectance values of the original and the spatially degraded satellite images. The main findings of our research were: (a) the Near Infrared (NIR) and Short-wave Infrared (SWIR) are the most important channels to estimate the percentage of burned area, whereas the NIR and red channels are the most important to estimate the percentage of vegetation in fire-affected areas; (b) when the bi-spectral space consists only of NIR and SWIR, then the NIR ground reflectance value plays a more significant role in estimating the percent of burned areas, and the SWIR appears to be more important in estimating the percent of vegetation; and (c) semi-burned areas comprising 45–55% burned area and 45–55% vegetation are spectrally closer to burned areas in the NIR channel, whereas those areas are spectrally closer to vegetation in the SWIR channel. These findings, at least partially, are attributed to the fact that: (i) completely burned pixels present low variance in the NIR and high variance in the SWIR, whereas the opposite is observed in completely vegetated areas where higher variance is observed in the NIR and lower variance in the SWIR, and (ii) bare land modifies the spectral signal of burned areas more than the spectral signal of vegetated areas in the NIR, while the opposite is observed in SWIR region of the spectrum where the bare land modifies the spectral signal of vegetation more than the burned areas because the bare land and the vegetation are spectrally more similar in the NIR, and the bare land and burned areas are spectrally more similar in the SWIR. Numéro de notice : A2013-237 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.isprsjprs.2013.02.016 En ligne : https://doi.org/10.1016/j.isprsjprs.2013.02.016 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=32375
in ISPRS Journal of photogrammetry and remote sensing > vol 79 (May 2013) . - pp 199 - 210[article]Exemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 081-2013051 RAB Revue Centre de documentation En réserve L003 Disponible Evaluation of different methods to retrieve the hemispherical downwelling irradiance in the thermal infrared region for field measurements / Vicente Garcia-Santos in IEEE Transactions on geoscience and remote sensing, vol 51 n° 4 Tome 2 (April 2013)
[article]
Titre : Evaluation of different methods to retrieve the hemispherical downwelling irradiance in the thermal infrared region for field measurements Type de document : Article/Communication Auteurs : Vicente Garcia-Santos, Auteur ; Enric Valor, Auteur ; et al., Auteur Année de publication : 2013 Article en page(s) : pp 2155 - 2165 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Acquisition d'image(s) et de donnée(s)
[Termes IGN] analyse comparative
[Termes IGN] données de terrain
[Termes IGN] éclairement énergétique
[Termes IGN] effet atmosphérique
[Termes IGN] emissivité
[Termes IGN] nébulosité
[Termes IGN] nuage
[Termes IGN] radiomètre
[Termes IGN] rayonnement infrarouge thermique
[Termes IGN] réflectance spectrale
[Termes IGN] réflexion diffuse
[Termes IGN] température de surfaceRésumé : (Auteur) The thermal infrared hemispherical downwelling irradiance (HDI) emitted by the atmosphere and surrounding elements contributes through reflection to the signal measured over an observed surface by remote sensing. This irradiance must be estimated in order to obtain accurate values of land-surface temperature (LST). There are some fast methods to measure the HDI with a single measurement pointing to the sky at a specified viewing direction, but these methods require completely cloud-free or cloudy skies, and they do not account for the radiative contribution of surrounding elements. Another method is the use of a diffuse reflectance panel (usually, a rough gold-coated surface) with near-Lambertian behavior. This method considers the radiative contribution of surrounding elements and can be used under any sky condition. A third possibility is the use of atmospheric profiles and a radiative transfer code (RTC) in order to simulate the atmospheric signal and to calculate the HDI by integration. This study compares the HDI estimations with these approaches, using measurements made on four different days with a completely clear sky and two days with a partially cloudy sky. The measurements were made with a four-channel CIMEL Electronique radiometer working in the 8–14-u spectral range. The HDI was also estimated by means of National Centers for Environmental Prediction atmospheric profiles introduced in the MODTRAN RTC. Additionally, the measurements were made at two different places with very different environments to quantify the effect of the contributing surroundings. Results showed that, for a clear-sky day with a minimal contribution of the surroundings, all methods differed from each other between 5% and 11%, depending on the spectral range, and any of them could be used to estimate HDI in these conditions. However, in the case of making surface measurements in an area with significant surrounding elements (buildings, trees, etc.), HDI values retrieved from the panel present an increase of +3 W . m-2 . um-1} compared with the other methods; this increase, if ignored, implies to make an error in LST ranging from +0.5°C to +1.5°C, depending on the spectral range and on surface emissivity and temperature. Comparison under heterogeneous skies with changing cloud coverage showed also large differences between the use of panel and the other methods, reaching a maximum difference of +4.6W . m-2 . um-1, which implies to make an error on LST of +2.2°C. In these cases, the use of the diffuse reflectance panel is proposed, since it is the unique way to capture the contribution of the surroundings and also to adequately measure HDI for sky changing conditions. Numéro de notice : A2013-221 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/TGRS.2012.2209891 En ligne : https://doi.org/10.1109/TGRS.2012.2209891 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=32359
in IEEE Transactions on geoscience and remote sensing > vol 51 n° 4 Tome 2 (April 2013) . - pp 2155 - 2165[article]Exemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 065-2013041B RAB Revue Centre de documentation En réserve L003 Disponible GSICS inter-calibration of infrared channels of geostationary imagers using Metop-IASI / Tim J. Hewison in IEEE Transactions on geoscience and remote sensing, vol 51 n° 3 Tome 1 (March 2013)
[article]
Titre : GSICS inter-calibration of infrared channels of geostationary imagers using Metop-IASI Type de document : Article/Communication Auteurs : Tim J. Hewison, Auteur ; Xiangqian Wu, Auteur ; Fangfang Yu, Auteur ; et al., Auteur Année de publication : 2013 Article en page(s) : pp 1160 - 1170 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Acquisition d'image(s) et de donnée(s)
[Termes IGN] erreur systématique
[Termes IGN] étalonnage relatif
[Termes IGN] image Feng-Yun
[Termes IGN] image GOES
[Termes IGN] image hyperspectrale
[Termes IGN] image Météosat
[Termes IGN] image MetOp-IASI
[Termes IGN] image thermique
[Termes IGN] rayonnement infrarouge thermique
[Termes IGN] régression linéaireRésumé : (Auteur) The first products of the Global Space-based Inter-Calibration System (GSICS) include bias monitoring and calibration corrections for the thermal infrared (IR) channels of current meteorological sensors on geostationary satellites. These use the hyperspectral Infrared Atmospheric Sounding Interferometer (IASI) on the low Earth orbit (LEO) Metop satellite as a common cross-calibration reference. This paper describes the algorithm, which uses a weighted linear regression, to compare collocated radiances observed from each pair of geostationary-LEO instruments. The regression coefficients define the GSICS Correction, and their uncertainties provide quality indicators, ensuring traceability to the selected community reference, IASI. Examples are given for the Meteosat, GOES, MTSAT, Fengyun-2, and COMS imagers. Some channels of these instruments show biases that vary with time due to variations in the thermal environment, stray light, and optical contamination. These results demonstrate how inter-calibration can be a powerful tool to monitor and correct biases, and help diagnose their root causes. Numéro de notice : A2013-123 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/TGRS.2013.2238544 En ligne : https://doi.org/10.1109/TGRS.2013.2238544 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=32261
in IEEE Transactions on geoscience and remote sensing > vol 51 n° 3 Tome 1 (March 2013) . - pp 1160 - 1170[article]Exemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 065-2013031A RAB Revue Centre de documentation En réserve L003 Disponible Mapping the distribution of ferric iron minerals on a vertical mine face using derivative analysis of hyperspectral imagery (430–970 nm) / R. Murphy in ISPRS Journal of photogrammetry and remote sensing, vol 75 (January 2013)
[article]
Titre : Mapping the distribution of ferric iron minerals on a vertical mine face using derivative analysis of hyperspectral imagery (430–970 nm) Type de document : Article/Communication Auteurs : R. Murphy, Auteur ; S. Monteiro, Auteur Année de publication : 2013 Article en page(s) : pp 29 - 39 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection
[Termes IGN] Advanced Visible & Near Infrared Radiometer
[Termes IGN] analyse d'image numérique
[Termes IGN] Australie occidentale (Australie)
[Termes IGN] dérivée
[Termes IGN] image hyperspectrale
[Termes IGN] mine de fer
[Termes IGN] photographie infrarouge couleur
[Termes IGN] rayonnement proche infrarouge
[Termes IGN] réflectance spectraleRésumé : (Auteur) Hyperspectral imagery is used to map the distribution of iron and separate iron ore from shale (a waste product) on a vertical mine face in an open-pit mine in the Pilbara, Western Australia. Vertical mine faces have complex surface geometries which cause large spatial variations in the amount of incident and reflected light. Methods used to analyse imagery must minimise these effects whilst preserving any spectral variations between rock types and minerals. Derivative analysis of spectra to the 1st-, 2nd- and 4th-order is used to do this. To quantify the relative amounts and distribution of iron, the derivative spectrum is integrated across the visible and near infrared spectral range (430–970 nm) and over those wavelength regions containing individual peaks and troughs associated with specific iron absorption features. As a test of this methodology, results from laboratory spectra acquired from representative rock samples were compared with total amounts of iron minerals from X-ray diffraction (XRD) analysis. Relationships between derivatives integrated over the visible near-infrared range and total amounts (% weight) of iron minerals were strongest for the 4th- and 2nd-derivative (R2 = 0.77 and 0.74, respectively) and weakest for the 1st-derivative (R2 = 0.56). Integrated values of individual peaks and troughs showed moderate to strong relationships in 2nd- (R2 = 0.68–0.78) and 4th-derivative (R2 = 0.49–0.78) spectra. The weakest relationships were found for peaks or troughs towards longer wavelengths. The same derivative methods were then applied to imagery to quantify relative amounts of iron minerals on a mine face. Before analyses, predictions were made about the relative abundances of iron in the different geological zones on the mine face, as mapped from field surveys. Integration of the whole spectral curve (430–970 nm) from the 2nd- and 4th-derivative gave results which were entirely consistent with predictions. Conversely, integration of the 1st-derivative gave results that did not fit with predictions nor distinguish between zones with very large and small amounts of iron oxide. Classified maps of ore and shale were created using a simple level-slice of the 1st-derivative reflectance at 702, 765 and 809 nm. Pixels classified as shale showed a similar distribution to kaolinite (an indicator of shales in the region), as mapped by the depth of the diagnostic kaolinite absorption feature at 2196 nm. Standard statistical measures of classification performance (accuracy, precision, recall and the Kappa coefficient of agreement) indicated that nearly all of the pixels were classified correctly using 1st-derivative reflectance at 765 and 809 nm. These results indicate that data from the VNIR (430–970 nm) can be used to quantify, without a priori knowledge, the total amount of iron minerals and to distinguish ore from shale on vertical mine faces. Numéro de notice : A2013-030 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.isprsjprs.2012.09.014 En ligne : https://doi.org/10.1016/j.isprsjprs.2012.09.014 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=32168
in ISPRS Journal of photogrammetry and remote sensing > vol 75 (January 2013) . - pp 29 - 39[article]Exemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 081-2013011 RAB Revue Centre de documentation En réserve L003 Disponible Topographic and thermal mapping of volcanic terrain using the AVTIS ground-based 94-GHz dual-mode radar/radiometric imager / D. Macfarlane in IEEE Transactions on geoscience and remote sensing, vol 51 n° 1 Tome 2 (January 2013)PermalinkThe spatial prediction of tree species diversity in savanna woodlands of Southern Africa / G. Mutowo in Geocarto international, vol 27 n° 8 (December 2012)PermalinkAn in-depth simulation of EnMAP acquisition geometry / P. Schwind in ISPRS Journal of photogrammetry and remote sensing, vol 70 (June 2012)PermalinkPermalinkTesting a near-infrared Lidar mounted with a large incidence angle to monitor the water level of turbid reservoirs / S. Tamari in ISPRS Journal of photogrammetry and remote sensing, vol 66 n° 6 supplement (December 2011)PermalinkIntegration of panoramic hyperspectral imaging with terrestrial lidar data / T. Kurz in Photogrammetric record, vol 26 n° 134 (June - August 2011)PermalinkL'image aérienne proche infrarouge : une information essentielle pour l'étude et la cartographie de la végétation / Jean Guy Boureau in Rendez-vous techniques, n° 31 (hiver 2011)PermalinkA low-cost multi-sensoral mobile mapping system and its feasibility for tree measurements / Anttoni Jaakkola in ISPRS Journal of photogrammetry and remote sensing, vol 65 n° 6 (November - December 2010)PermalinkDigital imagery for coastal monitoring / M. Cotchin in GEO: Geoconnexion international, vol 9 n° 8 (september 2010)PermalinkEvaluation of the influence of local fuel homogeneity on fire hazard through Landsat-5 TM texture measures / Cristina Vega-Garcia in Photogrammetric Engineering & Remote Sensing, PERS, vol 76 n° 7 (July 2010)Permalink